Amongst known electrosurgical generators is a generator which provides different radio frequency (RF) output waveforms for tissue cutting, for tissue coagulation, and for blended cutting and coagulation, the latter being performed by rapidly alternating between a waveform suitable for cutting and a waveform suitable for coagulation. U.S. Pat. No. 6,416,509 (Goble et al) and U.S. Pat. No. 3,885,569 (Judson) disclose such generators.
WO-A-96/37156 (Issa) discloses a resectoscope having an electrode assembly with two loop electrodes. RF cut and coagulation currents are supplied simultaneously to the loop electrodes from an output transformer unit, the current passing through the patient to a grounding or return pad placed against the patient's skin.
U.S. Pat. No. 6,966,907 (Goble) teaches a generator delivering cutting and coagulating waveforms by alternating constantly between a waveform limited to a first predetermined voltage threshold value and one limited to a second, different, predetermined threshold value to form a blended signal. The disclosed system also includes means for feeding the waveform to an instrument having three or more electrodes such that a cutting RF waveform is delivered between a first pair of electrodes and a coagulating waveform is delivered between a second pair of electrodes.